To better understand the invention, one must first understand the structure and function of the devices for which the mount is intended for use. A good example of such a device is an illuminator, a miniature high-intensity light source which is used to illuminate worksites. One exemplary illuminator is the ZEON illuminator sold by Orascoptic Research, Inc. (Madison, Wis., USA), and the illuminator illustrated and described in U.S. patent application Ser. No. 08/447,357 filed May 23, 1995 by Orascoptic Research, Inc. Thus far, the prior art has generally used dedicated mounts to attach illuminators to spectacles and other head- and body-mounted apparata, such as headbands. Where spectacles are concerned, these mounts utilize flanges which define slots wherein the frames of spectacles can be mounted, and they only allow attachment of an illuminator to particular sizes, types, and/or models of spectacles. These mounts cannot be used on all spectacles because the wide variance in spectacle frame dimensions--from thin wire frames for standard eyeglasses to thick plastic frames for safety glasses--is incompatible with the particular sizes or size ranges of frames for which each specific mount is designed to operate. However, a user may want to use an illuminator on different types of spectacles with widely different sizes and configurations during the course of work, as when switching to a new type of dental/medical procedure. As a result, when a user wants to use an illuminator on different spectacles, the mount(s) must be changed as well as the spectacles themselves. It is highly inconvenient to cease work to fit the illuminator in another mount, especially when the illuminator is being used in a time-sensitive medical or dental procedure. Additionally, because an illuminator is difficult to sterilize, it is generally undesirable for the user to reach up from a worksite to detach it from one pair of spectacles and/or mount in order to attach it to another. If the illuminator is not sterile, this can contaminate the user's hands, or alternatively the user's hands can contaminate the illuminator.
Because the prior art mounts are designed to fit on specific sizes and/or size ranges of spectacles, they also tend to slip on the spectacles after they are mounted if the mounts and spectacles are not a precise fit. This can lead to inadvertent repositioning of the illuminator's light beam, which poses the problem noted above in that the user may then be unable to reposition the illuminator in the proper orientation during a procedure without cross-contamination. Further, slippage of the mount and repositioning of an illuminator can be inconvenient or dangerous during the course of a dental or medical operation because the worksite may then lack needed illumination, and the user's hands may be occupied so that the user cannot reach up to reposition the illuminator. If slippage is significant, it can also lead to the possibility that the mount and illuminator will actually fall from the spectacles onto a worksite during the course of an operation.
Conversely, there can also be the problem that an illuminator is so firmly mounted to the spectacles that it becomes difficult to remove. Prior art mounts and illuminators can be bulky and somewhat heavy when worn on spectacle frames, and additionally the illuminators may grow hot, heating the user's forehead and causing sweat to run into the user's eyes. Therefore, it may be desirable or necessary to remove the mount and illuminator from the spectacles during the course of an operation. It may be undesirable to actually remove the spectacles themselves while doing so, e.g., in environments where safety glasses are recommended. However, the mounts may fit too tightly to allow removal without dislodging or removing the spectacles. This is particularly true when only one hand is free for use in effecting removal of the mount.
Additionally, the inventors believe that illuminators are most effectively used when their light beams coincide as closely as possible to the user's line of sight, as when the illumination is provided from a point between the user's eyes. This arrangement, which will be referred to as coaxial illumination, allows the user to view the interiors of very small cavities (e.g., a hole drilled in a tooth) without any obstructing shadows. The prior art mounts generally provide mounting for illuminators which allows only an approximation of coaxial illumination.
Prior art mounts can also be disadvantageous in that once they are affixed to spectacles, they may set the illuminator in a single fixed position, and thus orient the light beam of the illuminator in a single fixed direction. If the illuminated spot is not coincident with the area the user desires to be illuminated, the user has no remedy. As an example, if the illuminated spot is slightly too high or too low when the user wears the spectacles, the edge of the spot may be situated on a critical area on the worksite. This can be extremely irritating to the user because half of the critical area will be brightly illuminated, while the other half will be in relative darkness owing to the adjustment of the user's eyes to the bright spot.
To summarize, the prior art has thus far been unable to develop a mount which allows attachment of an illuminator to a broad range of differently-sized spectacles in a manner which allows precise positioning of the illuminator in a coaxial direction, which allows repositioning of the axis of the light beam to a desired angle, and which is highly resistant to slippage and repositioning of the illuminator on the spectacles. The present invention is intended to address these problems within a small, lightweight, and inexpensively-constructed mount.